Low radial profile needle safety device

ABSTRACT

A needle safety device has an outer tube within which a syringe barrel is slideably receivable. A collar in the outer tube is moveable relative thereto and rotatably attachable to the distal end of the barrel. A force member biases the outer tube in a distal direction. A track is formed in the inner surface of the outer tube. A pin extending radially outwardly from the collar slidingly engages the track. In a staging position, the barrel is inspectable. In a pre-injection position, the cannula extends a first length beyond the outer tube. In a full-insertion position, the cannula extends a second length greater than the first length beyond the outer tube. In a locked position, the cannula is entirely within the outer tube.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Division of application Ser. No. 14/383,364 filedon Sep. 5, 2014, which is a 371 of International ApplicationPCT/US13/29518, filed Mar. 7, 2013, which was published in the Englishlanguage on Sep. 12, 2013 under International Publication No. WO2013/134465 A1, which claims the benefit of U.S. Provisional Application61/607,711 filed on Mar. 7, 2012, the disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention is directed to a low radial profile needle safetyshield for syringes, in general, and for pharmaceutical syringes inparticular.

Needlestick injuries are a well known occupational hazard for healthcareworkers. Unintended needlesticks have the potential for transmittingblood-borne viruses such as hepatitis B and C and the humanimmunodeficiency virus (HIV) to the recipient. After a needlestickinjury, certain procedures must be followed to minimize the risk ofinfection for the recipient, such as laboratory blood tests andpost-exposure prophylaxis started immediately after exposure to apathogen, such as one of the aforementioned viruses, in order to preventinfection by the pathogen and the development of the associated disease.

Conventional safety devices intended to reduce the frequency ofpost-injection needlesticks typically have a sheath partially orcompletely surrounding the pharmaceutical syringe. The sheath may beheld in a retracted position exposing the needle for aspiration andinjection and may be automatically deployed around a needle afterwards.

Among the drawbacks of many conventional prior art needle safety devicesis that they are not compatible with current accepted practice due tosizes and configurations that are incompatible with conventional fillingand sterilization equipment and methods.

Accordingly, there is a need in the art for a safety injection devicehaving a low radial profile.

BRIEF SUMMARY OF THE INVENTION

Briefly stated, one aspect of the invention is a needle safety devicefor an injection device having a generally cylindrical barrel with adistal end from which a cannula extends. The needle safety devicecomprises an outer tube within which the barrel is slideably receivable.The outer tube has a distal end, a proximal end spaced from the distalend and a longitudinal axis. A collar in the outer tube is moveablerelative thereto and is rotatably attachable to the distal end of thebarrel. A force member is between the outer tube and the collar andbiases the outer tube in a distal direction. A track S is formed in theinner surface of the outer tube. A pin extending radially outwardly fromthe collar 14 slidingly engages the track S. The track S comprises afirst track segment extending from a staging position to a pre-injectionposition. The proximal end of the outer tube is in a position relativeto the distal end of the barrel allowing the barrel to be inspected whenthe collar is attached to the distal end of the barrel and the pin isreleaseably retained in the staging position by a first catch in theouter tube. The cannula extends a first length beyond the distal end ofthe outer tube when the collar is attached to the distal end of thebarrel and the pin is releaseably retained in the pre-injection positionby a second catch in the outer tube. A second track segment contiguouswith the first track segment extends from the pre-injection position toa full-insertion position. The cannula extends a second length greaterthan the first length from the distal end of the outer tube when thecollar is attached to the distal end of the barrel and the pin is in thefull-insertion position. A third track segment contiguous with thesecond track segment extends from the full-insertion position to alocked position in which the pin is immovably retainable in a portion ofthe third track segment spaced from and parallel to a portion of thefirst track segment. The cannula is entirely within the outer tube whenthe collar is attached to the distal end of the barrel and the pin isimmovably retained in the locked position by a third catch in the outertube.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofpreferred embodiments of the invention, will be better understood whenread in conjunction with the appended drawings. For the purpose ofillustrating the invention, there is shown in the drawings embodimentswhich are presently preferred. It should be understood, however, thatthe invention is not limited to the precise arrangements andinstrumentalities shown.

In the drawings:

FIG. 1 is a side perspective view of an embodiment of the lowradial-profile needle safety device in a staging position on the barrelof a pharmaceutical injection device in accordance with the presentinvention;

FIG. 2 is an exploded side perspective view of the needle safety deviceof FIG. 1,

FIG. 3 is an side cross-sectional view of the safety device of FIG. 1;

FIG. 4 is a side perspective view of the outer tube of the safety deviceof FIG. 1;

FIGS. 5 and 6 are side cross-sectional views of the outer tube of thesafety device of FIG. 1 showing the track in the outer tube;

FIG. 7 is a top perspective view of the collar of the safety of FIG.1;

FIG. 8 is a side perspective view of another embodiment of the lowradial-profile needle safety device in a staging position on the barrelof a pharmaceutical injection device in accordance with the presentinvention;

FIG. 9 is an exploded side perspective view of the needle safety deviceof FIG. 8,

FIG. 10 is an side cross-sectional view of the safety device of FIG. 8;

FIG. 11 is a front elevation view of the outer tube of the safety deviceof FIG. 8;

FIG. 12 is a right side elevation view of the outer tube of the safetydevice of FIG. 8;

FIG. 13 is a side cross-sectional view of the outer tube of the safetydevice of FIG. 8;

FIG. 14 is a top plan view of the collar of FIG. 8; and

FIGS. 15A-15D is a sequence of side elevation views of the safety deviceand a portion of a pharmaceutical syringe of FIG. 1 showing progressivepositions of the safety device relative to the pharmaceutical insertiondevice.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments of the invention,examples of which are illustrated in the accompanying drawings. Theterminology used in the description of the invention herein is for thepurpose of describing particular embodiments only and is not intended tobe limiting of the invention.

As used in the description of the invention and the appended claims, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. The words“and/or” as used herein refers to and encompasses any and all possiblecombinations of one or more of the associated listed items. The words“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

The words “right,” “left,” “lower” and “upper” designate directions inthe drawings to which reference is made. The words “inwardly” and“outwardly” refer to directions toward and away from, respectively, thegeometric center of the needle safety shield, and designated partsthereof. The terminology includes the words noted above, derivativesthereof and words of similar import.

Although the words first, second, etc., are used herein to describevarious elements, these elements should not be limited by these words.These words are only used to distinguish one element from another. Forexample, a first segment could be termed a second segment, and,similarly, a second segment could be termed a first segment, withoutdeparting from the scope of the present invention.

As used herein, the word “distal” means in a direction away from thehand of a user holding the injection device immediately prior toinjecting a medicament (e.g., the end of the barrel from which thecannula extends is the distal end of the barrel) and “proximal” meanstoward the hand of a user holding the injection device immediately priorto injecting a medicament.

The following descriptions are directed towards various embodiments of aneedle safety shield in accordance with the present invention.

Referring to the drawings in detail, where like numerals indicate likeelements throughout, there is shown in FIGS. 1-7 a preferred embodimentof a low radial profile needle safety device, generally designated 10,and hereinafter referred to as the “safety device” 10 in accordance withthe present invention. The safety device 10 is for use with an injectiondevice 1, such as a pharmaceutical syringe. The injection device 1 maybe a pre-filled; however, the present invention is not so limited. Forexample, the injection device 1 may be nearly any type of pharmaceuticalsyringe, including those to be filled by a patient or user, for example.

The injection device 1 preferably has a generally cylindrical barrel 2having a distal end 2 a and an opposing proximal end 2 b. A cannula (orneedle) 3 extends from the distal end 2 a of the barrel 2 and is influid communication with a bore of the barrel 2. The cannula 3 may beremovably attached to the distal end 2 a of the barrel 2. Alternatively,and preferably, the cannula 3 is fixedly attached thereto. A removableshield 4 covers the cannula 3. Typically, the distal end 2 a of thebarrel 2 is configured as a tapered hub 5 that may have a variety ofconfigurations, such as an inverted frustum, a cylinder or a sphere.Preferably, the hub 5 has a generally circular or bulbous shape thatextends radially outwardly or beyond at least some other portion of thedistal end 2 a of the barrel 2. However, the hub 5 is not limited to thesize, shape and/or configuration shown and described herein

Although the barrel 2 may be formed of nearly any material capable ofsafely enclosing medicaments, it is preferably formed of glass or apolymeric material. The injection device 1 may be pre-filled with amedicament or may be provided without a medicament for filling by theuser.

A piston rod and piston (not shown) are slidably receivable in the boreof the barrel 2. The piston rod may have a free proximal end thatextends from the proximal end of the barrel.

The safety device 10 comprises an outer tube 12 within which the barrel2 is slideably receivable. The outer tube 12 has a distal end 12 a, aproximal end 12 b and a longitudinal axis A. A collar 14 is in the outertube 12 and is movable relative thereto. In some embodiments, the collar14 is fixedly attachable to the distal end 2 a of the barrel 2. In otherembodiments, the collar 14 is rotatably attachable to the distal end 2 aof the barrel 2. A force member 16, such as a compressible coil spring,is provided between the outer tube 12 and the collar 14. The forcemember biases the outer tube 12 in a distal direction. A track S isformed in the inner surface 13 of the outer tube 12. A pin 18 extendingradially outwardly from the collar 14 slidingly engages the track Swhich, in turn, guides the movement of the pin 18 and therefore thecollar 14 within the outer tube 12.

Referring to FIG. 7, in a preferred embodiment, the collar 14 has thegeneral shape of a hollow cylinder terminating at the distal end with anannulus 20 having a central bore 22 sized to receive and retain thedistal end 2 a of the barrel 2 or the hub 5 if the distal end 2 a of thebarrel 2 is configured as a hub. The annulus 20 is sufficientlycompliant and sized to allow passage of the hub 5 through the bore 22and then to rotatably engage the hub 5. The outer surface of the annulus20 has a generally circular channel 24 to receive one end of the forcemember (e.g., a coil spring) 16. A circumferential step 26 (see, FIG. 3)in the inner surface 13 of the outer tube 12 is sized to receive andengage the distal end 14 a of the force member 16. At least one pin 18extends radially outwardly form the collar 18 and is slidably receivablein the track S. In embodiments in which the outer tube 12 has aplurality of tracks, the collar 14 may have a corresponding plurality ofpins.

To mount the collar 14 to the barrel 2, the distal end 2 a of the barrel2 or the hub 5 may be inserted into and through the proximal end 14 b ofthe collar 14 and into and through the distal end 14 a of the collar 14.As the huh 5 passes through the distal end 14 a of the collar 14, thebore 22 in the annulus 20 expands until the hub 5 passes completelytherethrough. The annulus 20 then return to its initial state in whichthe distal end 14 a of the collar 14 abuts the proximal surface 5 b ofthe hub 5, thereby rotatably attaching the collar 14 on the barrel 2between the hub 5 and a shoulder or enlarged portion of the distal end 2a of the barrel 2.

Referring to FIGS. 5 and 6, in some embodiments, the track S comprisesthree track segments. A first track segment S₁ is provided to allow thesafety device 10 to be assembled and inspected after the collar 14 hasbeen attachment to the distal end 2 a of the barrel 2 as discussedabove. The first track segment S₁ extends from a staging position (i)shown in FIG. 15A having a first catch 32 to a pre-injection position(ii) shown in FIG. 15B having a second catch 34 and has as a profile aninitial portion (a) substantially parallel to the longitudinal axis A ofthe outer tube 12 followed by a final portion (h) angled with respect tothe longitudinal axis A and serving as a cammed surface. When the collar14 is attached to the distal end 2 a of the barrel 2 and the pin 18 isin the staging position (i), the proximal end 12 b of the outer tube 12is in a position relative to the distal end 2 a of the barrel 2 allowingthe barrel 2 to be inspected.

During the assembly process, the force element 16 is inserted in theouter tube 12. The collar 14, attached to the distal end 2 a of thebarrel 2, is then inserted in the outer tube 12 such that the pin 18 (orplurality of pins, if there is a plurality of tracks) is in the firsttrack segment S₁ (or plurality of first track segments). The outer tube12 is moved in the proximal direction causing an initial compression ofthe force element 16 as the pin 18 travels to the beginning of the firsttrack segment S₁ and becomes releasably retained in the first catch 32thereby securing the outer tube 12 in the staging position (i).

As the outer tube 12 moves in the proximal direction causing the forcemember 16 to be compressed, the pin 18 travels the initial portion ofthe first track segment S₁ and is guided to the pre-injection position(ii) by the cammed surface which imparts an angular rotation to thecollar releasably securing the pin 18 in second catch 34 When the collar14 is attached to the distal end 2 a of the barrel 2 and the pin 18 isin the second catch 34, the cannula 3 extends a first length L₁ beyondthe distal end of the outer tube 12. The length L1 of cannula extensiondepends on the particular size and configuration of the insertion device1. At a minimum the length of extension allows visualization of thedistal most tip of the cannula 3 at an insertion location prior topenetration of the skin.

A second track segment S₂ contiguous with the first track segment S₁extends from the pre-injection position (ii) to a full-insertionposition (iii) shown in FIG. 15C. The second track segment S₂ is angledwith respect to the longitudinal axis of the outer tube 12 and has anarcuate profile (c).

At the initiation of an injection, the distal end 12 a of the outer tube12 makes contact with the skin. The force applied by the skin to theouter tube 12 moves the pin 18 out of the first catch 32 and alongbeginning of the second track segment S₂. As the skin is beingpenetrated by the cannula 3, continued application of force by the skinto the outer tube 12 further moves the outer tube 12 in the proximaldirection and the pin 18 in the distal direction along the second tracksegment S₂ to the fully inserted position (iii). When the collar 14 isattached to the distal end 2 a of the barrel 2 and the pin 18 is in thefull-insertion position the cannula 3 extends a second length L₂ greaterthan the first length L₁ from the distal end 12 a of the outer tube 12.The length L2 of cannula extension at the full-insertion position (iii)depends on the particular size and configuration of the insertion device1 and the subcutaneous location the medicament is to be delivered. Thesecond track segment guides the pin 18 along a generally arcuate pathimparting both axial translation and rotation to the collar 14. Theouter tube 12 remains in the full-insertion position (iii) untilwithdrawal of the cannula 3 is initiated, typically after a full dose ofthe medicament is delivered.

A third track segment S₃ contiguous with the second track segment S₂extends from the full-insertion position (iii) to a locked position (iv)shown in FIG. 15D having a third catch 36 in which the pin 18 isimmovably retainable. The third track segment S₃ has an initial portion(d) extending from the full-insertion position (iii) substantiallyparallel to the longitudinal axis of the outer tube followed by anarcuate profile (e) providing a caromed surface terminating in anaxially extending locked position (iv). As the cannula 3 is beingwithdrawn after the desired dose of medicament has been delivered, theforce applied by the skin to the outer tube 12 decreases and the outertube 12 moves in the distal direction relative to the collar 14 underthe reactive force of the force member 16 compressed between the collarand the outer tube. The third track segment S₃ initially guides the pin18 substantially parallel to the longitudinal axis and then along agenerally arcuate path imparting both axial translation and a rotationto the collar and finally into the locked position (iv). When the collar14 is attached to the distal end 2 a of the barrel 2 and the pin 18 isimmovably retained in the third catch 36, the outer tube 12 fully coversthe cannula 3 in the entirety and is prevented from moving in either theproximal or distal directions.

Referring to the drawings in detail, where like numerals indicate likeelements throughout, there is shown in FIGS. 8-14 another preferredembodiment of a low radial profile needle safety device, generallydesignated 100, and hereinafter referred to as the “safety device” 100in accordance with the present invention. The safety device 100 is alsofor use with the injection device 1 disclosed above.

The safety device 100 comprises an outer tube 112 configured to slidablyreceive therein a portion of the distal end 2 a of the barrel 2. Atleast one track S′ is formed in the inner surface 113 of the outer tube112. The at least one track S′ has a plurality of contiguous segmentsfurther discussed below. In some embodiments, the inner surface 113 mayhave a plurality of tracks, each having the same configuration,positioned in a spaced-apart, aligned arrangement. A portion of theouter tube 112 has a generally U-shaped cut therethrough forming aflexible tongue 138 having a radially disposed ramp 140.

A collar 114 is slidably received in the outer tube 112. The collar 114is attachable to the distal end 2 a of the barrel 2. At least one pin118 extends radially outwardly from a sidewall of the collar 114 and isslidably received in the at least one track S′ formed in the innersurface 113 of the outer tube 112. In embodiments in which the outertube 112 may have a plurality of tracks S′, the collar 114 may have acorresponding plurality of pins 118 projecting radially outwardly fromspaced-apart locations around the circumference of the sidewall. A forcemember 116 extending between the outer tube 112 and the collar 114biases the outer tube 112 in a distal direction. In some embodiments,opposed ends of the force member 116 may be received and retained in acircumferential channel 124 in the outer surface of the collar 114 and acircumferential step 126 in the inner surface 113 of the distal end 112a of the outer tube 112.

Referring to FIG. 14, in a preferred embodiment, the collar 114 is abody of revolution having a bore 122 therethrough and includes at leastone and preferably four spaced-apart fingers 128 fixedly attachable tothe distal end 2 a of the barrel 2. Each finger 128 is sufficiently'compliant to allow passage of the hub 5 through the bore 122 of thecollar 114 and then to return to an initial configuration. Each finger128 preferable is configured to conform to the size and/or shape of acorresponding portion of the distal end 2 a of the barrel 2. A gap orspacing 130 is preferably located between adjacent fingers 128, whichallows for the collective expansion and contraction of the four fingers128.

A channel formed in the distal end 128 a of each finger 128 collectivelyforms a circular channel 124 in the outer surface of the collar 114 toreceive one end of the force element 116. A circumferential step 126(see, FIGS. 12 and 13) in the inner surface 113 of the outer tube 112 issized to receive and engage the distal end of the force member 116.Diametrically opposed pins 118 extends radially outwardly from thecollar 114 and are sized to slidingly engage the at least one track S′formed in the inner surface 113 of the outer tube 112.

To mount the collar 114 to the barrel 2, the hub 5 may be inserted intoand through the proximal end 114 b of the collar 114 and into andthrough the distal end 114 a of the collar 114. As the hub 5 passesthrough the distal end 114 a of the collar 114, each of the fingers 128may flex radially outwardly from the longitudinal axis A until the hub 5passes completely therethrough. The fingers 128 then return to theirinitial state in which the distal end 128 a of each finger 128 abuts theproximal surface 5 b of the hub 5, thereby immovably attaching thecollar 114 in place on the barrel 2 between the hub 5 and a shoulder orenlarged portion of the distal end 2 a of the barrel 2. In someembodiments, the hub 5 may have a portion below the proximal surface 5 bhaving ribs that extend into the gaps 130 between the fingers 128further preventing rotation of the collar 114.

Referring to FIGS. 12 and 13, in a preferred embodiment, the track S′has a plurality of segments, each segment corresponding to a relativeposition of the outer tube 112 with respect to the distal end 2 a of thebarrel 2 and/or to the cannula 3 projecting from the hub 5.

A first track segment S₁′ is provided to allow the safety device 100 tobe assembled and inspected after the collar 114 has been attachment tothe distal end 2 a of the barrel 2 as discussed above. The first tracksegment S₁′ extends from a staging position (i) having a catch 132 to apre-injection position (ii) having a catch 134 and has as a profile aninitial portion a′ substantially parallel to the longitudinal axis ofthe outer tube followed by a circumferential portion b′ terminating inthe catch 134 in registry with the radially disposed ramp 140 on theflexible tongue 138 of the outer tube 112. When the collar 114 isattached to the distal end 2 a of the barrel 2 and the pin 118 is in thestaging position (i), the proximal end 112 b of the outer tube 112 is ina position relative to the distal end 2 a of the barrel 2 allowing thebarrel 2 to be inspected

During the assembly process, the force member 116 is inserted in theouter tube 112. The collar 118, attached to the distal end 2 a of thebarrel 2, is then inserted in the outer tube 112 such that the pins 118are in the catch 132 at the staging position (i). The outer tube 112 ismoved in the proximal direction causing the force member 116 to becompressed as the pins 118 travel the length of the initial portion a′of the first track segment S₁′. The outer tube 112 is then rotated tomove the pins 118 along the circumferential portion b′ until the pins118 become releasably retained in the catch 134 thereby securing theouter tube 112 in the pre-injection position (ii). When the collar 114is attached to the distal end 2 a of the barrel 2 and the pin 118 is inthe second catch 134, the cannula 3 extends a first length L₁ beyond thedistal end of the outer tube 112.

A second track segment S₂′, contiguous with the first track section S₁′,extends substantially parallel to the longitudinal axis A of the outertube 112 from the pre-injection position (ii) to the full-insertionposition (iii) of the outer tube. At the initiation of an injection, thedistal end 112 a of the outer tube 112 makes contact with the skin. Theforce applied by the skin to the outer tube 112 causes the flexibletongue 138 to deflect radially outwardly as the pin 118 moves out of thecatch 132, up the radially disposed ramp 140 and along the second tracksegment S₂′. As the skin is being penetrated by the cannula 3, continuedapplication of force by the skin to the outer tube 112 further moves theouter tube 112 in the proximal direction and the pins 118 in the distaldirection along the second track segment S₂′ to the full-insertionposition (iii). When the collar 114 is attached to the distal end 2 a ofthe barrel 2 and the pin 118 is in the full-insertion position (iii),the cannula 3 extends a second length L₂ greater than the first lengthL₁ from the distal end 112 a of the outer tube 112. The second tracksegment guides the pin 18 along a path substantially parallel to thelongitudinal axis of the outer tube 112. The outer tube 112 remains inthe full-insertion position (iii) until withdrawal of the cannula 3 isinitiated, typically after a full dose of the medicament is delivered.

A third track segment S₃′, contiguous with the second track segment S₂′,has a profile having an initial portion c′ extending from the fullyinserted position (iii) substantially parallel to the longitudinal axisA of the outer tube 112 to a mid portion d′ having a first extent d₁′angled with respect to the longitudinal axis A followed by a secondextent d₂′ parallel to the longitudinal axis A. The mid portion d′ isfollowed by a final portion e′ having an arcuate profile providing acammed surface terminating in an axially extending locked position (iv).

After a full dose of the medicament has been delivered, and withdrawalof the cannula 3 is initiated, the force applied by the skin to theouter tube 112 decreases. Under the reactive force of the compressedforce member 116, the outer tube 112 moves in the distal direction. Thepins 118 move in the proximal direction along the third track segmentS₃′ which guides the pins 118 in the initial portion c′ substantiallyparallel to the longitudinal axis A imparting to the outer tube 112translation in the axial direction without rotation. The first extentd₁′ of the mid portion d′ cams the pins 118 in a direction angled withrespect to the longitudinal axis A imparting to the outer tube 112translation in the axial direction with rotation. The second extent d₂′of the mid portion d′ guides the pins 118 substantially parallel to thelongitudinal axis A imparting to the outer tube 112 translation in theaxial direction without rotation. The final portion e′ of the thirdtrack segment S₃′ guides the pins 118 in a generally arcuate pathimparting to the outer tube 112 both axial translation and a rotationuntil the pins 118 are in the locked position (iv) in the catch 136. Inthe locked position, the outer tube 112 is fully extended covering thecannula 3 in the entirety and is prevented from moving in the distal orproximal directions.

The foregoing detailed description of the invention has been disclosedwith reference to specific embodiments. However, the disclosure is notintended to be exhaustive or to limit the invention to the precise formsdisclosed. Those skilled in the art will appreciate that changes couldbe made to the embodiments described above without departing from thebroad inventive concept thereof. Therefore, the disclosure is intendedto cover modifications within the spirit and scope of the presentinvention as defined by the appended claims.

We claim:
 1. A needle safety device for an injection device having agenerally cylindrical barrel with a distal end from which a cannulaextends, the needle safety device comprising: an outer tube within whichthe barrel is slideably receivable, the outer tube having a distal end,a proximal end spaced from the distal end of the outer tube and alongitudinal axis; a collar positioned within the outer tube, moveablerelative thereto and attachable to the distal end of the barrel; a forcemember positioned within the outer tube biasing the outer tube in adistal direction; a track formed in an inner surface of the outer tube;and a pin extending radially outwardly from the collar slidinglyengaging the track, wherein the track comprises: a first track segmentextending from a staging position to a pre-injection position, whereinthe proximal end of the outer tube is in a position relative to thedistal end of the barrel allowing the barrel to be inspected when thecollar is attached to the distal end of the barrel and the pin isreleaseably retained in the staging position by a first catch in theouter tube, and wherein the cannula extends a first length beyond thedistal end of the outer tube when the collar is attached to the distalend of the barrel and the pin is releaseably retained in thepre-injection position by a second catch in the outer tube; a secondtrack segment contiguous with the first track segment and extending fromthe pre-injection position to a full-insertion position, wherein thecannula extends a second length greater than the first length from thedistal end of the outer tube when the collar is attached to the distalend of the barrel and the pin is in the full-insertion position; and athird track segment contiguous with the second track segment andextending from the full-insertion position to a locked position in whichthe pin is immovably retainable, a portion of the third track segmentspaced from and parallel to a portion of the first track segment,wherein the cannula is entirely within the outer tube when the collar isattached to the distal end of the barrel and the pin is immovablyretained in the locked position by a third catch in the outer tube. 2.The needle safety device according to claim 1, wherein the collar is ahollow cylinder terminating at a distal end with an annulus rotatablyattachable to the distal end of the barrel.
 3. The needle safety deviceaccording to claim 1, wherein the first track segment has an initialportion substantially parallel to the longitudinal axis of the outertube followed by a final portion angled with respect to the longitudinalaxis.
 4. The needle safety device according to claim 1, wherein thesecond track segment is angled with respect to the longitudinal axis ofthe outer tube, has an arcuate profile and imparts both axialtranslation and rotation to the collar.
 5. The needle safety deviceaccording to claim 1, wherein the third track segment has an initialportion substantially parallel to the longitudinal axis of the outertube followed by an arcuate portion providing a cammed surfaceterminating in the third catch at the locked position.
 6. The needlesafety device according to claim 1, wherein the collar is a hollowcylinder terminating at a distal end with a plurality of spaced-apartfingers fixedly attachable to the distal end of the barrel.
 7. Theneedle safety device according to claim 1, wherein the outer tube has acut therethrough forming a flexible tongue having a radially disposedramp.
 8. The needle safety device according to claim 1, wherein theouter tube has a cut therethrough forming a flexible tongue having aradially disposed ramp in registry with the second catch and the firsttrack segment has an initial portion substantially parallel to thelongitudinal axis of the outer tube followed by a circumferentialportion terminating at the second catch.
 9. The needle safety deviceaccording to claim 1, wherein the second track segment is substantiallyparallel to the longitudinal axis of the outer tube.
 10. The needlesafety device according to claim 1, wherein the third track segment hasan initial portion substantially parallel to the longitudinal axis ofthe outer tube, followed by a mid-portion having a first extent angledwith respect to the longitudinal axis and a second extent parallel tothe longitudinal axis, followed by a final portion having an arcuateprofile providing a cammed surface terminating in the third catch at thelocked position.
 11. The needle safety device according to claim 1,wherein the outer tube moves only in axial translation without rotationwhen the cannula extends beyond the outer tube.
 12. The needle safetydevice according to claim 1, wherein the force member is positionedwithin the outer tube between the collar and the distal end of the outertube.